PORT ANGELES — Clallam County’s public works department is recommending the county move forward with a two-cell design option for the Dungeness off-channel reservoir.
At the commissioners’ work session on Monday, Commissioners Mark Ozias and Mike French indicated support for the design choice. Commissioner Randy Johnson was not in attendance.
The purpose of the reservoir is to improve management of the watershed and supply downstream properties with irrigation during the last 30 days of the season, said Steve Gray, deputy director of public works.
The reservoir will be located on an almost 400-acre parcel along River Road and Happy Valley Road south of the U.S. Highway 101.
The design that seems to be the most promising, called E1, will have about 960 acre-feet of storage capacity. Gray said the design would be split into two separate “cells” by an easement, which would avoid needing to relocate Bonneville Power Administration (BPA) infrastructure.
The other options include E2, which would join the two cells at the spot where the power lines are the highest. That would increase the reservoir’s storage space while theoretically keeping the BPA infrastructure in place. It would have about 1,240 acre-feet of storage.
To gain about 220 more acre-feet, option E3 would require the county to rebuild a portion of the site’s roadway. Gray said he doesn’t recommend pursuing that option.
“I don’t believe the added costs from moving the road … would be a good way to go,” he said.
E4 would have the largest storage capacity at just more than 1,600 acre-feet. That would completely span the BPA easement and require relocation of that infrastructure, Gray said.
Although E1 had the smallest storage capacity of all the options, Gray said analysis indicates it would contain just enough water to meet late-season needs.
“There would be enough water to serve the last 30 days of those immediate downstream properties served by irrigation,” he said.
Additionally, since E1 is a two-cell format, Gray said there would be the option to expand it to something similar to the E4 option in the future. However, if E4 were immediately chosen, not only would it be more expensive, it also would add three to four years to the process.
One of the reasons E1 seems to be the most promising is due to costs, Gray said. It is cheaper than all the other options, and, because of its two-cell format, it could be constructed in phases, if funding requires it.
To date, Gray said about $2.24 million has been spent on design work for the reservoir. All of it has been grant funded.
If E1 is chosen, Gray said it likely will take another $1.3 million to $1.6 million to get the project to 90 percent of final design.
Currently, there is about $800,000 left from the 2019 stream flow restoration grant that the county received from the state Department of Ecology. That leaves a $500,000 to $800,000 funding gap. If the county decides to pursue option E4, Gray said it could add another $2 million in design costs.
To close the gap, Gray said funds secured for the construction costs could potentially be reallocated for design.
Once the county reaches the construction phase, there could be a range of costs, depending on the design. E1 would cost about $36.6 million while E4 would be closer to $49.3 million.
These estimates are higher than estimates from a few years ago, Gray said, due to inflation and rising costs.
The county has been awarded or is being considered for construction grants totaling $33.7 million. Assuming none of those funds are reallocated to design work, that would leave between a $2.9 million and $15.6 million funding gap.
In addition to working on the reservoir design, public works and the Dungeness Reservoir Work Group are working on site cleanup and upstream and downstream improvement designs.
The goal is that the property will be a county park where people can continue to hike, bike and ride horses. Gray said he recommends calling it the “Dungeness Trails County Park.”
“I can’t think of a better name,” he said.
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Reporter Emma Maple can be reached by email at emma.maple@peninsuladailynews.com.
